(CBS/AP) UNITED NATIONS - The U.N. high commissioner for human rights said Monday that the flow of arms to both the Syrian government and the opposition risks escalating the conflict, which "must be avoided at all costs."

In a written statement to the Security Council, Navi Pillay talked of reported strikes by attack helicopters, torture on detainees and that "the bulk of information gathered to date" on the mass killings in Houla earlier this year indicates that the government-supported Shabiha militias and regime of Syrian President Bashar Assad were responsible.

"The conflict is becoming increasingly sectarian and gradually eroding the fabric of society," Pillay says in her statement. "The lack of protection for civilians in Syria is becoming more acute with increasing civilian casualties and limited access to humanitarian assistance and basic services."

Pillay says arming both the opposition and the Assad regime will lead to further violence.

"The testimony of the U.N. human rights chief is significant because it shows that both the government of Syria and the opposition are continuing to pursue a military solution, despite political efforts to resolve the conflict," CBS News foreign affairs analyst Pamela Falk reports from the U.N. "The high commissioner told the U.N. that both the government and the opposition are arming themselves for continued fighting, and that means more civilians will be killed."

"The systematic torture and inhumane treatment of detainees, including children and women, remain of grave concern," Pillay says. "Recently, [the Office of the High Commissioner for Human Rights] interviewed victims of multiple forms of torture, including severe beatings, electric shocks, cigarette burns, mock executions, sleep deprivation and psychological torture. Detainees are also held in inhumane conditions and deprived of water, food and medical care."

Pillay called on the Security Council to strengthen the suspended U.N. observer mission in Syria and asked that Syria be referred to the International Criminal Court in The Hague.

The 300-member U.N. mission in Syria repeatedly came under fire before the U.N. suspended it last month, and its future is not clear. The council is awaiting a report from Secretary-General Ban Ki-Moon on options for the mission.

Pillay said the mission's presence in Syria remains vital. "Ending the conflict is what we all seek, and any solution to the conflict must adequately address the root cause of the conflict, namely the human rights grievances," she said.

The conflict has killed more than 14,000 people since the revolt began in March 2011, according to opposition estimates. The fighting has grown increasingly militarized in recent months, with rebel forces launching attacks and ambushes on regime targets.

Pillay spoke after briefing the council Monday in New York. The briefing followed an international conference held by international envoy Kofi Annan in Geneva on Saturday. The conference endorsed a U.N.-brokered peace plan that calls for the creation of a transitional government in Damascus, but at Russia's insistence it left the door open to Assad being part of an interim administration.

Russia would likely block any attempt to refer Syria to the ICC. The court prosecutes accusations of genocide, crimes against humanity and war crimes when national authorities are unwilling or unable to do so.

Pillay said anti-government forces are accused of using children as human shields. She said if the Syrian government grants her staff access, she is ready to send it to investigate the claim.

France's U.N. Ambassador Gerard Araud said Syria will remain too dangerous for U.N. observers until a political process gets under way.

"The mission itself can't stop the violence, so we need a political process, that was the reason why we had this meeting in Geneva," he said. "If by any chance there is a political process, the observers will be necessary and useful. If not, we will have to look at the options of closing or downgrading it."

Araud said France supports referring Syria to the ICC but said there is no agreement on the issue.